Linux notes 2-5 lvm-expandable disk

5.lvm*********************
For creating an extensible disk

# # 1.LVM Build # #
pvs              //View physical Volume information
vgs               //View physical volume group information
LVs               //View Logical Volume Information
established:
Fdisk/dev/vdb                  //divides the physical partition and modifies the partition ID to 8e
pvcreate/ DEV/VDB1             //Creating a physical volume
Vgcreate hello/dev/ VDB1      //Creating a physical volume group
lvcreate-l 100m-n lv0 Hello  //Creating a logical volume

Test:

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# # 2.LVM Management # #

# #扩展磁盘 # #--supported disk extensions in use
Lvextend-l 200m/dev/hello/lv0//Extended Logical volume size to 200M
Xfs_growfs/dev/hello/lv0//Extended file system

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PVCREATE/DEV/VDB2//Create physical volume

Vgextend HELLO/DEV/VDB2//Extended Physical volume

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It seems that the partition size can be infinitely extended, but the fact is limited by the file system, the partition size can not be infinitely extended, for example, XFS file system support maximum partition size of 18EB

# #缩减磁盘 # #

Note: XFS does not support file system reduction, which causes the disk to not shrink, so we use the Ext file system for this experiment

Shrink file System--You must uninstall the device before shrinking
umount/mnt///unloading equipment
E2fsck-f/dev/hello/lv0//testing equipment
Resize2fs/dev/hello/lv0 200M//Shrink file system to 200M

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Reduce the logical volume size--You must shrink the file system size before reducing the logical volume size
Lvreduce-l 200m/dev/hello/lv0
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reduced physical volume

remove VDB1
pvmove/dev/vdb1/dev/ VDB2                      //moving VDB1 data to VDB2
Vgreduce hello/dev/vdb1                       //Remove the
PVREMOVE/DEV/VDB1 from the physical volume group                              //Deleting a physical volume

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Problems that may occur in the operation

1> reduced file system size is larger than the logical volume size, causing the device to become unusable
Workaround extend the logical volume size before performing a reduced file system, reducing the size of the logical volume
2> not remove device from physical volume, delete device directly in Fdisk
An unknown partition appears in the physical volume, and the Vgreduce--removemissing Physical volume group is used to remove the unknown device

# # 3.LVM Snapshot # #--Keep your data safe

Write Data on disk
Mount/dev/hello/lv0/mnt
touch/mnt/file{1..10}
Ls/mnt

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Create a Snapshot
Umount/mnt
Lvcreate-l 10m-n lv0-backup-s/dev/hello/lv0
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Delete data

Mount/dev/hello/lv0-ba ckup/mnt

Ls/mnt

rm-fr/mnt/*

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Re-create the snapshot
Umount/mnt
Lvremove/dev/hello/lv0-backup
Lvcreate-l 10m-n lv0-backup-s/dev/hello/lv0

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Data recovery
Mount/dev/hello/lv0-backup/mnt
Ls/mnt

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# # 4.LVM Delete # #--deleted sequentially

Lvremove//deleting snapshots and logical volumes

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Vgremove//Deleting physical volume groups

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Pvremove//Deleting physical volumes

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# 5. Command and script create partition # #

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Linux notes 2-5 lvm-expandable disk